Cleanup workaround in testcase.py

Signed-off-by: Daniel Nephin <dnephin@docker.com>

tests/integration/testcases.py

@@ -42,34 +42,23 @@ class DockerClientTestCase(unittest.TestCase):
         if 'command' not in kwargs:
             kwargs['command'] = ["top"]
 
-        links = kwargs.get('links', None)
-        volumes_from = kwargs.get('volumes_from', None)
-        net = kwargs.get('net', None)
+        workaround_options = {}
+        for option in ['links', 'volumes_from', 'net']:
+            if option in kwargs:
+                workaround_options[option] = kwargs.pop(option, None)
 
-        workaround_options = ['links', 'volumes_from', 'net']
-        for key in workaround_options:
-            try:
-                del kwargs[key]
-            except KeyError:
-                pass
-
-        options = ServiceLoader(working_dir='.', filename=None, service_name=name, service_dict=kwargs).make_service_dict()
+        options = ServiceLoader(
+            working_dir='.',
+            filename=None,
+            service_name=name,
+            service_dict=kwargs
+        ).make_service_dict()
+        options.update(workaround_options)
 
         labels = options.setdefault('labels', {})
         labels['com.docker.compose.test-name'] = self.id()
 
-        if links:
-            options['links'] = links
-        if volumes_from:
-            options['volumes_from'] = volumes_from
-        if net:
-            options['net'] = net
-
-        return Service(
-            project='composetest',
-            client=self.client,
-            **options
-        )
+        return Service(project='composetest', client=self.client, **options)
 
     def check_build(self, *args, **kwargs):
         kwargs.setdefault('rm', True)